In semiconductor technology, an integrated circuit pattern can be defined on a substrate using a photolithography process. Dual damascene processes are utilized to form multilayer copper interconnections including vertical interconnection vias/contacts and horizontal interconnection metal lines. During a dual damascene process, a plug filling material is employed to fill in the vias (or contacts) and the material is then polished back. However, the vias (or contacts) are defined by a different lithography process and may cause misalignments between the underlying metal lines and the vias. Especially, when the semiconductor technologies move forward to advanced technology nodes with smaller feature sizes, such as 20 nm, 16 nm or less, the misalignments have less tolerance and may cause short, opening or other issues.
Therefore, the present disclosure provides an interconnection structure and a method making the same to address the above issues.